Welcome Dan. As Detlef has confirmed, yes this is mammoth molar. Mostly this is found in rather contemporary efforts, though there are a few old exempts about. Your entire ensemble appears to be fairly recent.
These threads might tell you more about this material.
http://www.vikingsword.com/vb/showth...=mammoth+molar
http://www.vikingsword.com/vb/showth...=mammoth+molar